Base CampThis field
station on Seymour Island in Antarctica served as the research
base from which fossil-collecting expeditions were launched
on previous excursions. During this trip  UI geologist
Dan Blake's third  the crew will be based on a ship
from which the fossils will be cataloged and packed for shipment.

Geologist Dan Blake
is not dreaming of a white Christmas. In fact, hes dreading snow
in December. Thats because Blake, a professor from the UI, hopes
to be collecting fossils on a small island off the Antarctic Peninsula,
and a blanket of snow would stop his work cold.

Although December falls during summer in the Southern Hemisphere, the
Antarctic weather will be far from warm, with temperatures hovering
near freezing. "Any snowfall will cover the fossils and halt our
collecting," he said. "Then, all we can do is sit around and
hope that it melts before we have to head home."

In addition to the occasional blizzard, the expedition to Seymour Island
presents other hazards as well. "Antarctica is not a user friendly
place," said Blake, who had to pass a rigorous health exam as a
requirement for going on the trip. "Its not necessarily unsafe,
but you must be careful and avoid risks. If you get into serious trouble,
the nearest physician is thousands of miles away."

This will be Blakes third trip to Seymour Island. During previous
expeditions, he and colleague Richard Aronson  a marine biologist
at the Dauphin Island Sea Lab in Alabama  documented how a long-term
trend of declining temperature in Antarctica at the end of the Eocene
epoch disrupted certain predator-prey relationships.

Local residentPenguins
are one of the local residents of Seymour Island, which is
about 13 miles long and from 2 to 5 miles wide. It is called
an "oasis" because it has extensive dry valleys
with bare rock and little snow. Volcanic dust deposited within
the valleys promotes the melting of any snow and ice, leading
to further exposure of the rock surface, which makes it ideal
for collecting fossils.

Global climate change
late in the Eocene had an important influence in Antarctica. "This
was the beginning of the transition from a cool-temperate climate in
Antarctica to the polar climate that exists there today," Blake
said. "The cooling trend strongly

influenced the structure
of shallow-water communities, and these effects are still evident in
the peculiar ecological relationships among species living today."

The researchers
early work concentrated on populations of crinoids and brittlestars.
"We argued that as the temperature cooled, it upset the balance
of nature and resulted in reduced predation," Blake said. "Now
we want to go back and examine effects of predation in more detail by
studying populations of other organisms  specifically snails and
clams."

Some of the snails the researchers are interested in earned their livelihood
by drilling holes in the shells of clams and extracting the tender meat
inside. Cooling temperatures reduced the abundance of fish and crabs,
which in turn altered predation patterns of the snails that fed upon
the clams. A number of outcomes of these changes are possible, each
of which will be interpreted differently.

"For example, the drilling of clams by predatory snails could increase
with time, since the drillers themselves were subject to lower predation
pressure as temperatures declined," Blake said. "Drilled shells
in this outcome will become more common through time. We will look for
and compare such changes in predation rates as we walk through the stratigraphic
section and across the climatic change revealed in the rocks."

The fossil record has many exciting things to say about both past and
present marine ecology, Blake said. "The fossil outcrops on Seymour
Island provide a unique opportunity to learn how climate change affected
Antarctic marine communities. Understanding the response of fossil faunas
to global cooling in the late Eocene will provide insight into the rapidly
changing structure of modern communities."

Funded by the National Science Foundation, this years trip will
involve a weeklong reconnaissance mission on the island  in preparation
for a five-week-long fossil-hunting expedition to occur next year. The
research team includes Blake, Aronson and Blakes graduate student,
Alex Glass.

"Its very important for students to go on such field expeditions,"
Blake said. "In addition to the adventure, they can learn an aspect
of geology that they just cant learn in the laboratory
as long as it doesnt snow."